Wine and Hygiene Management: Considering the Nature of Wine Character

Food should be hygienic.

This seems like a given for those of us living in the modern era. However, Japan's Food Sanitation Law was actually enacted in 1948, just 75 years ago. In 2018, this law was partially revised, making it mandatory for all food businesses to implement hygiene management based on HACCP (Hazard Analysis and Critical Control Point) principles. The concept of food hygiene is far newer than we might think.

Winemaking, on the other hand, has been practiced long before such concepts were established. Recent research suggests that the ancestors of wine grapes appeared on Earth 11,000 years ago, and winemaking began 2,000 years later. This means winemaking has a history spanning 9,000 years.

Despite this long history, while winemaking has become more technologically sophisticated through the introduction of machinery and equipment, the fundamental processes remain unchanged today. Grapes are harvested from vineyards, crushed, fermented, and bottled. Unlike sake production, there is essentially no washing of the raw material (grapes), and pasteurization before or after bottling is rarely performed. Moreover, unfiltered wines that skip the filtration process before bottling have recently gained popularity, creating phenomena that seem to run counter to hygiene management principles.

Given this situation, questions arise about wine's level of hygiene. Just how hygienic is wine? Do different wine styles result in varying degrees of hygiene? And fundamentally, how hygienic should wine be? Let us examine these questions from the perspective of basic winemaking principles and recent trends.

Why Wine Doesn't Require Sterilization

Not all wines worldwide are produced without any sterilization processes. For example, sulfites (SO2), known as antioxidants, serve this purpose. While their primary function is preventing oxidation as their name suggests, they also suppress microbial activity.

Some wines undergo pasteurization (low-temperature sterilization) before bottling, and others use enzymes that neutralize specific microorganisms. While these methods fall short of complete sterilization, they suppress the activity of microorganisms in wine and prevent quality deterioration.

However, the fundamental premise is that wine requires little to no sterilization or sterilization processes. Indeed, winemaking methods have not changed dramatically from those used in eras when hygiene management concepts barely existed. This demonstrates that continuing traditional methods has not resulted in serious health hazards such as food poisoning.

The reason wine has avoided major health issues without requiring special hygiene management lies in its low pH and relatively high alcohol content.

Wine contains high levels of acids, which keep the pH relatively low. Low pH alone inhibits microbial growth, but the antimicrobial effect of SO2 is further enhanced in low-pH environments. This means sufficient effects can be achieved with smaller amounts of SO2, and if the same amount used in high-pH environments is added, the antimicrobial effect becomes even stronger.

The fact that most wines have alcohol content between 10-14% is also crucial. Alcohol has sterilizing properties, so higher alcohol content increasingly suppresses microbial growth and activity. These characteristics are why wine is said to require no special sterilization treatment.

Is Sterilization Really Unnecessary for Wine?

Whether sterilization is unnecessary for wine depends heavily on how that wine is produced.

If only completely healthy grapes are used as raw materials, fermentation is carried out with dry yeast, the wine is finished as a dry style with virtually no residual sugar, appropriate amounts of SO2 are added, storage occurs with minimal oxygen contact, and proper filtration is performed before bottling, then that wine is sufficiently protected from microbial contamination and requires no special sterilization process. However, if different methods are adopted at any stage of the winemaking process, the risk of microbial contamination increases with each deviation.

While wine is thought not to spoil, mold can grow on the liquid surface inside bottles before opening in cases such as sweet wines with high residual sugar content where oxygen infiltration into bottles increases during long-term storage. If acetic acid bacteria somehow enter the wine, their metabolism could turn it into vinegar. Although various external conditions are involved, wine is not absolutely immune to spoilage in environments where factors leading to deterioration exist. In fact, pasteurization technology is said to have been developed to prevent wine spoilage.

Since sterilization processes aim to eliminate as many factors as possible that could lead to such deterioration at that point in time, sterilization processes are necessary in winemaking depending on the conditions.

The Concept of "Hygiene" in Wine

When considering wine's hygiene management, questions remain about how appropriate it is to use the term "hygiene." The antonym of "hygiene" is "unsanitary," but in wine terms, this "unsanitary" condition primarily refers to wine being exposed to microbial contamination. However, situations that invite such microbial contamination are not necessarily "unsanitary" environments in the general sense.

In winemaking, the relationship with microorganisms is an inseparable and extremely important element. Most of wine's gorgeous and diverse aromas and flavors are created through the activity of various microorganisms. Therefore, countless types of microorganisms exist in winemaking facilities, and problems arise only when some of these perform metabolism unfavorable to humans, making them targets for hygiene management.

However, some microorganisms that perform undesirable metabolism do not always engage in such metabolism, behaving instead like opportunistic pathogens. In other words, some microorganisms can have positive or negative effects depending on the situation, making it impossible to eliminate all microorganisms from winemaking facilities in the name of hygiene management.

This means we cannot simply classify near-sterile conditions as hygienic and conditions with high microbial counts as unsanitary.

Fermentation Cannot Eliminate Microorganisms

During wine grape harvest season, images and videos of people crushing grapes with their feet in containers filled with grapes are commonly seen. While less common recently, some may have witnessed scenes of people directly entering fermentation vessels.

Before mechanization reached winemaking, grapes were crushed by human feet, and people would directly enter fermentation tanks to warm the juice to fermentation-appropriate temperatures using body heat. Such practices continue at some wineries even today, despite the widespread adoption of press machines and temperature control equipment.

The idea of people treading barefoot on something that will later be consumed, or even immersing themselves in it, might seem unthinkable. However, surprisingly many producers deliberately adopt these methods, considering them natural winemaking approaches and appropriate techniques that allow for subtle adjustments impossible with machinery. The rationale supporting these producers is based on low pH, maintenance of anaerobic conditions through fermentation, and the sterilizing effects of rising alcohol content. The theory is that wine sterilizes itself through fermentation, so treading barefoot or immersing in the juice before fermentation poses no major problems.

The Reality of Dominance in Enology

Wine enology teaches that when specific yeasts become dominant during fermentation, the activity of other microorganisms is suppressed. This is indeed true and has been confirmed through multiple studies. However, what is less known is that this "dominance" actually represents dominance in a state where the dominant organism comprises less than half of the total population. While dominant, it does not enjoy overwhelming dominance.

The yeast primarily used in making fermented beverages like wine, sake, and beer is a species called Saccharomyces cerevisiae. While this yeast is noted for inhibiting the activity of other surrounding microorganisms to secure its dominant position, even these efforts never result in 100% presence of this yeast in fermenting juice. This means numerous other types of microorganisms exist in fermenting juice, and some cases see these organisms surviving until after fermentation.

Among microorganisms that survive fermentation and continue to exist in some form after fermentation, some may be harmless to humans while others could be harmful. Furthermore, they might benefit the wine or have undesirable effects. The types of microorganisms present in any given wine vary by year, vineyard, and even individual fermentation vessels. Additionally, slight changes occur depending on timing, making it difficult to completely understand what exists there. However, the more actions are taken that allow external microorganisms to enter, the higher the likelihood that such microorganisms will be present in the wine.

Microorganisms include those with high alcohol tolerance and those without, those strong in acidic environments and those that are weak, representing a mixture of various characteristics. Even if any microorganisms enter the wine, immediate effects do not necessarily appear. However, contrary to what some producers have traditionally believed, complete elimination of such microorganisms through fermentation cannot be expected, and considering that fermentation completely eliminates microbial risks is no longer realistic.

When wine is in a state where it might be affected by some microorganisms, changes in the wine's taste and aroma typically appear before harmful effects on human health manifest. Undesirable microbial metabolism in wine is also a major cause of off-flavors detected in wine.

The Complex Relationship Between Hygiene Management and Complexity

Wine's great appeal is said to lie in its complex aromas and flavors. Despite being made from grapes as a single raw material, the ability to perceive various aromas and flavors not found in grapes themselves is mysterious, and this mystery continues to captivate us.

Many of these aromas are related to microbial metabolism in some way. Various microorganisms performing various types of metabolism create various aromas and flavors. In this sense, creating conditions where more microorganisms exist in wine would enable the production of wines with greater complexity containing more aromas and flavors. In fact, some producers have recently begun releasing wines with styles not found in conventional wines by deliberately incorporating acetic acid nuances and Brett (Brettanomyces) nuances that were previously unconditionally rejected.

When microorganisms previously called spoilage yeasts are utilized to give wine character, the relationship with wine's hygiene level becomes problematic. From a hygiene perspective, spoilage yeasts are, as their name suggests, targets whose very existence cannot be permitted. However, when attempting to deliberately utilize these yeasts, it becomes necessary to partially relax hygiene management perspectives. While spoilage yeasts represent an extreme example, if any microorganisms are to be utilized in winemaking, conflict with hygiene management concepts becomes unavoidable.

How can both approaches be reconciled? Finding that answer is certainly not simple.

How to Approach Hygiene Management

One of the major movements currently visiting the wine industry is a return to origins. Producers who objected to modernization in production have turned their attention to classical winemaking techniques, recently releasing wines made in styles called natural wine or natural wine to the world. The fact that wine consumption has come to be perceived not as simple alcoholic beverage consumption but as one method of lifestyle expression has strongly supported this movement, resulting in markets now flooded with wines claiming to be natural, unfiltered, and SO2-free.

One factor contributing to this enthusiasm for returning to origins among producers can be found in the rapid commoditization resulting from wine standardization. Through the spread of modernized production equipment and the generalization of various knowledge including enology, much of the wine circulating in markets has become standardized to high levels. This made it difficult for some producers to express the individuality they had previously been able to showcase. The establishment of environments where anyone could produce reasonably high-quality wine led to the mass production of wines with similar characteristics. The expansion of this loss of wine individuality is thought to have been significantly influenced by improvements in hygiene management standards.

In recent years, in addition to introducing hygienic production equipment, the generalization of hygiene management concepts has dramatically improved cleanliness levels within wineries. As a result, the range of activity for microorganisms that created wine individuality became restricted, likely leading to wine standardization.

Originally, food production facilities becoming more hygienic is desirable and there is no reason to oppose this. However, in situations where giving one's products individuality is required to survive increasingly fierce competition, it would not be surprising if producers wished to return to previous states where this could be achieved more easily rather than attempting to realize it within strict restrictions. Fortunately, winemaking with its 9,000-year history offers countless stories to justify returning to the past. Creating wine individuality alongside romantic stories also pleases consumers.

The importance of giving wine individuality is beyond dispute. However, the means sought to achieve this differs according to each producer's philosophy. This can also change depending on consumer preferences. Since wine is ultimately a luxury good, no one—whether on the production or consumption side—should interfere with others' preferences. However, while respecting such individual preferences, certain quality and hygiene standards must be maintained. The necessity of maintaining consistent quality even at the cost of sacrificing some wine characteristics should be a point that most people can understand and agree upon.

Perhaps in times like these, it is necessary to reconsider recent wine styles and producer philosophies from such perspectives.

The degree to which microorganisms might actually survive through winemaking processes is discussed in detail in our premium content.